Method of twisting yarn in centrifugal machines



v. VATY ETAL April 14, 1959 METHOD OF TWISTING YARN IN CENTRIFUGAL MACHINES Filed Nov. so, 1958- 2 Sheets-Sheet 1 FIG. 7

I I I I METHOD OF TWISTING YARN IN CENTRIFUGAL MACHINES Filed Nov. 30. 1956 'v. SVATY ET AL April 14, 1959 2 Sheets-Sheet 2 v no.3.

Z F I Vlad/m Ir Ivory: fir? 1/64/1547 United States Patent NLETHOD OF TWISTING YARN IN CENTRIFUGAL MACHINES Vladimir Svaty and Jiri Libansky, Liberec, Czechoslovakl a, asslgnors to Mira, zavody na pleten a stavkov zbozi, narodni podnik, Prague, Czechoslovakia Application November 30, 1956, Serial No. 625,514 1 Claim. (Cl. 57-457 The present invention relates to a method of twisting or craping yarn in centrifugal machines.

A process has been known for twisting or craping of yarn in centrifugal machines in which twist is imparted to the yarn in two phases, namely one part of the twist during winding-off the yarn from the bobbin and depositing it into a can of the centrifugal machine and the other part of the twist when the deposited yarn is withdrawn from the can, while the centrifugal machine rotates permanently in the same direction. The second phase of the twist is performed by taking the can of the centrifugal machine from its spindle and placing it on another spindle, while securing the end of the yarn to another bobbin on which the yarn is wound. In carrying out this process the centrifugal machine has to be stopped in order to place the can on another spindle and to secure the end of the yarn to the take-up bobbin. Attached to this second bobbin is a device which in a known way distributes the yarn along the bobbin in uniform layers. When the unwinding of the cake from the can is finished, the latter is placed again on the first spindle and the whole process repeated.

The drawbacks of the just described process are removed by the present invention. According to the main feature thereof the yarn is twisted or craped also in two phases during the transport of the yarn into the can and during the further unwinding from the can, but the process is simplified by proceeding in such a way that the winding of the yarn from the can on a bobbin, during which operation the second part of the twist is imparted to the yarn, is carried out on the same bobbin from which the yarn has been unwound in the first part of the formation of the twist. In order to make possible a simple transition from the unwinding to the take-up operation and thus also a change from the supply of yarn into the can to the withdrawal of the same from the can, the end of the yarn has to be rigidly secured to the tube of the bobbin, rotating permanently in the same sense.

The accompanying drawings represent an example of a device for carrying out the method according to the invention, wherein Fig. 1 shows a device for twisting or craping yarn with a centrifugal machine and a bobbin,

Fig. 2 shows securing of the end of the yarn to the tube,

Fig. 3 shows the arrangement of the tube for fastening the end of the yarn,

Fig. 4 shows a diagram of the unwinding operation from the bobbin, and

Fig. 5 shows the transition from the unwinding of the yarn into a new winding on the bobbin.

Referring to Fig. 1, the reference numeral 1 denotes the can of a centrifugal machine, 2 a tubular yarn guide mounted in a bearing 5 by means of an arm 3 and a vertical rod 4. The rod 4 receives reciprocal movement from a can mechanism (not shown) and transmits this movement to the tubular guide 2, which distributes the yarn 6 along the walls of the can, depositing the yarn Patented Apr. 14, 1959 i.e. double or multiple, according to the number of yarnsto be twisted. The yarn withdrawn from the bobbin 7 is threaded through an eyelet 23 and proceeds then through the guide 2. The free lower end 6 of the yarn is conveyed by the revolving can and the produced centrifugal force tensions the yarn.

The speed of supply of the yarn to the can and thus also the twist is controlled by an unrolling cylinder 8 against which the bobbin 7 is constantly pressed. This is effected c.g. by mounting the conical pivot of the bobbin 7 on a lever 9, rotatable around a pivot 10. The pressure force is produced either by a spring or weight (not shown), exerting a torque on the pivot 10 in the direction shown by the arrow 22.

The conical pivot 12 is mounted for rotation on the lever 9 so that the bobbin 7 may freely revolve around its axis. This makes possible the supply of yarn to the can with a constant velocity, determined by the circumferential velocity of the unrolling cylinder 8 and independent of the ratio in relation to the cross-wound bobbin 7. The initial portion of the yarns wound on the tube 11 is rigidly fastened to the tube e.g. by threading the leading end of the yarns 13 through an aperture 21 (Fig. 2) near the edge of the tube and clamping the same between the tube 11 and the conical pivot 12. In order to facilitate the threading of the yarn into the aperture 21, the marginal portion of the tube may be slotted as far as the aperture (Fig. 3).

The described device operates as follows:

The can of the centrifugal machine is set in rotation and the yarn 14, threaded through the tube of the yarn guide 2, is set in rotation with its lower end 6 by the influence of the rotation of air in the can and friction against the walls. By the produced centrifugal force the yarn is pulled against the walls of the can, where it is deposited. By a reciprocal movement of the guide 2 upwards and downwards, the yarn is deposited in uniform layers along the whole surface of the jacket of the can. By the rotation of the free end of the yarn one half of the required twist is imparted thereto. The velocity of supply into the can is controlled by the revolutions of the unrolling cylinder 8 against which the bobbin 7 is permanently pressed. By rolling along the cylinder 8 the yarn is unwound into the can.

As soon as the entire store of yarn on the bobbin 7 is unwound (Fig. 4), the unwinding operation is changed to a take-up operation (Fig. 5), as the original initial portion 13 of the yarns (Fig. 2) is rigidly fastened to the tube and continues to rotate with the same. This change of the unwinding into a take-up operation takes place entirely automatically and spontaneously without the sense of rotation of the unrolling cylinder 8 being changed. In this way the yarn starts to be wound back from the can to the same tube 11.

The yarn receives again a twist, which is added to the first twist produced during the supply of yarn into the can. In order to deposit the yarn on the bobbin in regular layers, it has to be distributed crosswise along the bobbin 7. This is effected by a guide 15 mounted for movement on a prismatic guiding rail 16. The guide 15 receives reciprocal movement in a known way by means of an axial eccentric known per se, not shown in the drawings, engaging a slot 17 of the guide 15. The guide is placed in such a way that the thread 14 during the unwinding of yarn from the bobbin 7 to the can 1 misses or by-passes the guide 15 and only when the process is reversed in the second half of the twisting operation, i.e. when the yarn is again wound on the tube 11 it may automatically snap into a guiding slot 18. The thread- 3 ing of the" thread into the guiding slot i's'fadilitated by zic'fiziriife? 19 erase outf edges' of the guide 15.

As soon as the whole cake 20' is rewoundon the bobbin 7, the lever 9 is rocked. aside, the bobbin 7 withdrawn off the conical pivot 12 and the machine is ready far e further" twis'tifig' e' seraticin.

The" desefibd Method of t-Wistifig yarn in at centrifugal nitiehiri e has at be? of advantages as compared with the hit'l'i'e'rtdkno ethods;

1*) The unwinding and take-up operation is-e'flfeet'ed 611 the Bobbin; which results in a saving of bobbins;

(*2) The" twisted or c'r-ap'ed yarn iswound directly on crew-wanna c'oiie's' the winding or spooling of cops being dispensed with.

(-3) The bobbin 7 r matee ermanentl in the same sense duringtli'e unwinding and talking-up of the yarn and winding. device is verysirnple"; no reversing apparatusof reversing of the movement of the bobbin being req'uiied.

4' eatemat e operation of the'=twistingproees's is 20 iiidepeiicie'nt dfthe length of yarn wound on the bobbin. No failure caused by a bfeal'rrdwn' of the gauging means or of thefi'iiiii''-e"nd stop" niotion can occur here.

(5) The: devicemetres of bobbins.

A method of twisting yarn comprising the steps of securely fastening an end of the yarn to a bobbin prior to Winding of the yarn on the latter, unwinding the yarn from the bobbin into the rotated pot of a centrifugal machine to impart a twist to the yarn while the bobbin is rotated in a predetermined direction; and continuing to rotate said bobbin in said? predetermined direction following the unwinding of the full length of the yarn so that the latter is rewo'und' on said bobbin and further twisted during return of the arnfrom' the rotated pot onto said bobbin.

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